


To Know Your Enemy

by lore_shark



Category: Ao no Exorcist | Blue Exorcist
Genre: Alternate Universe - Fantasy, Alternate Universe - Royalty, Art, Blood and Violence, Enemies Fake Dating to Lovers, Enemies to Lovers, Eventual Romance, Eventual Smut, M/M, Other Additional Tags to Be Added, Slow Burn, There's a war, Worldbuilding
Language: English
Status: In-Progress
Published: 2020-06-21
Updated: 2020-06-20
Packaged: 2021-03-03 21:28:57
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,978
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24832399
Author URL: https://archiveofourown.org/users/lore_shark/pseuds/lore_shark
Summary: Gehenna and Assiah, rival nations caught up in a decades long war.Enemy princes willing to try anything to end the fighting.Rin and Ryuuji may just have a way to find peace, if they can manage not to kill each other in the process.----------A collab piece between myself and Lakes! I write, she draws, it's beautiful! Enjoy!
Relationships: Okumura Rin/Suguro "Bon" Ryuuji
Comments: 34
Kudos: 45





	To Know Your Enemy

_There is no winner in war._

Rin paused atop the crown of a once great monument, its intricately carved face now shrouded in moss and battle scars, and growled at the words rattling like dice in his head, turning over and over and over until he was sick of hearing them; he didn’t know what Shiro wanted from him. His mentor had always been confusing, teaching him lessons on peace and trade with one hand and tactics of war with the other. 

He shook off his tumbling thoughts and forced himself to focus on the fighting in the stony fields below. The ruins of an abandoned temple sanctuary littered the grassy hill, their beauty lost beneath decades of bloodshed. Even now, new blood ran thick across the once white stone. He watched Gehenna’s army push steadily into the Assiah'n forces, driving them back into the dry river bed at the base of the temple grounds. Come spring, the river would flow fast and hard with mountain ice melt. Now, though, it rang with the sounds of shouting and struck metal.

From his place high above, the fighting looked like nothing more than a grisly dance, waves of warriors blending into a shifting, faceless sea. It was familiar, a scene he’d seen a hundred times in a hundred different fields.

It was familiar, and Rin hated it.

His fingers tightened instinctively around the handle of his sword and he tilted out of his crouch as he spotted a streak of blond and black hair in the tumult; Suguro Ryuuji, heir to Assiah’s throne and sworn enemy of the Gehennan nation. The man was steadily chanting from the saddle of his kama, motes of silver aether gathering around them as his beast twisted through the ebb and surge of struggling soldiers.

Rin’s gaze raked across the field, searching for Suguro’s target; silver meant wind, air, movement… “Crap!” The demon launched himself from the statue’s head, claws sparking on the age worn stone as he slid to the monument’s base. He kicked off just before reaching the ground, arcing through the air and catching the side of a crumbling wall. He scrambled to the top and bolted along the narrow parapet, ignoring the fighting below him. He needed to reach the Torii gate before Suguro; there was no telling where the human was planning to port himself.

A set of arrows thunked into the stone behind Rin as he ran and he turned to find a group of mounted humans leveling their bows for another round. He waited for the volley to loose before pulling on his internal fire and setting flame to the arrows’ fletching; they wobbled off uselessly in every direction. Smirking, Rin flicked his attention back to his chase. Suguro’s kama was gaining ground, flowing between pockets of clashing men and demons like rushing water, its long body practically contorting out of the way. The creature eyed him cooly, clacked its beak in his direction, and then bounded over a cracked and crumbled fountain. Rin snarled at it.

The Torii gate loomed large before them, perched atop a short set of mossy stone steps. Its once vibrantly red columns were now faded and scratched and ringed with thorny vines. Even so, pale silver aether swirled in its center, a swiftly growing portal forming. Suguro’s eyes snapped from the gate to Rin, narrowing darkly as he continued chanting. There was no time left to get in front of him, to cut his mantra short, so Rin pelted up the steps, bared his fangs, and leapt at the foreign prince. 

They hit the portal together. 

A wash of searing cold poured into Rin’s bones, lancing straight through the wool of his chuba coat and armor, and he thought for a moment that maybe he was dying; which, that sort of sucked, but at least he’d taken Suguro with him. 

And then there was light and a teeth rattling jolt as the three of them shot through the portal’s far side, bouncing apart like shards from a dropped vase. Rin landed flat on his back in a deep snow drift, stunned for a moment before his senses kicked back in. He was surrounded by snow, and the sky above was a dark bruised grey, and the wind was bitingly cold, and- “Damn you Suguro!” Rin yelled, clawing his way back to his feet and clambering out of his self made hole to point a black taloned finger at the similarly enraged prince, “Why the hell did you port us into the damn mountains?”

There was no telling how far they were from the battle still raging along Assiah’s border, but it was obvious they’d ended up high in the Gehennan mountain range. Everything around them screamed abandoned settlement; besides the Torii gate, now quiet and still and very obviously lacking a portal, there were a handful of neglected buildings, a small empty shrine in the plateau’s center, and a crude tunnel leading somewhere into the mountain. Rin noted, belatedly, just how close he’d come to tumbling straight off the plateau’s edge. 

“You think I was actually aiming for this place?” Suguro shouted as he stood, placing a steadying hand on his mount’s furred shoulder to avoid slipping on the ice. His cheeks and ears were flushed bright pink from the chill and he was shivering fiercely under his thin platemail and silk. “I wouldn’t be here if you hadn’t messed up my damn incantation!” 

Rin scowled, fingers twitching. “Yeah? Then where the hell were you going?”

“That’s none of your damn business, demon.” Suguro bit back. He clicked his tongue and thumped his fist on the kama’s side; it immediately charged forward, its many legs slipping and skidding across the icy ground, short wings flaring as it tried to spear Rin on its tapered beak. The demon jolted out of the way, hissing furiously and crouching low, predatory. He let the beast rush past him before he lashed out, snagging its tail in his claws and jerking harshly through the silky fur. It screeched as he tore into soft flesh, rounding on him with surprising flexibility and a well trained intent to kill.

Rin spun and kicked off the nearest boulder, leaping up and over the kama as it snapped at him, the beast just managing to catch the edge of his coat sleeve in its mouth. He twisted his arm free of the armored fabric and used his new momentum to drop onto the kama’s feathered back, snarling thickly, sharp teeth aimed for its throat when he finally registered the sound of chanting nearby.

Suguro was once again on his knees, whole body shaking in the frigid wind as he fought to breath the thin, frozen air, stubbornly pushing himself to spin verse after verse of a foreign cantrip. It was obvious the man wasn’t accustomed to the high altitude like Rin’s people, and his light armor, though well suited for Assiah’s warm hills, was utterly useless now. The kama bucked hard beneath Rin, using the moment of distraction to shuck the demon off while it scrabbled to get its footing. Rin hit the ground with a curse and immediately bolted for Suguro, desperate for the second time that afternoon to silence the other prince’s deep, rich voice. He had no idea what aria the man was reciting and he absolutely did not want to find out.

Thin, razor like talons sliced through Rin’s pant leg, just missing his ankle but tripping him up nonetheless. He ducked into the fall, dodging the kama’s stabbing beak while rolling onto his back; he hiked his legs up to his chest, flared his claws, and kicked ruthlessly into the creature’s ribs. It stumbled backwards, narrowly avoided crushing Suguro, and toppled into a snow drift; the beast wheezed hoarsely in the high mountain air, unable to right itself. Rin stood quickly, tail twitching behind him, its tufted end flicking with restrained instinct as he fought down the urge to kill the battered kama. He had more important matters to deal with instead, like shutting up the chanting prince.

Suguro straightened where he knelt, sitting tall on his knees as he locked his gaze with Rin, stubborn and determined in the face of his enemy, never once breaking his recitation. Pale green aether pooled around his hands, a sure sign he was close to finishing his aria. A deep, bubbling growl worked its way up and out of Rin’s chest at the sight; he didn’t know if he should be more awed or infuriated by the show of resilience, the knowledge that his enemy would push himself to such extremes.

The prince raised his glowing hands then and Rin lunged with a roar, thick fangs wide, tail lashing behind him as he spat vitriol and venom at the man. “I’m just a demon, yeah? You want to kill me so damn badly, don’t you?” He wrapped his hand around Suguro’s throat, lifting him from his knees before slamming his back into the snow. Rin followed him down, straddling his chest with strong thighs, growling and snapping his teeth and twisting his wrist until finally, _finally_ the human stopped chanting. “Why do you hate us so much?” Rin hissed, pressing his free hand into Suguro’s face, long black claws skittering over the silver jewelry in his nose and eyebrow, watching panic settle into his eyes as he struggled to breathe. 

He could kill him. 

In that moment, there on top of the world, Rin was perfectly positioned to rid himself of his greatest enemy. Suguro had no younger siblings, his parents were old and not likely to bear more children. He could end the Assiah’n royal line there and then, effectively end the entire fucking war. His fingers curled tighter and he felt the warmth of blood bloom beneath his nails. Gehenna would win and they’d finally be done fighting and-

_There is no winner in war._

Rin reeled back like he’d been struck, scrambling off of Suguro in a rush. 

He’d been so close, so _damned close_ , why the hell was he hesitating? Yukio would have done it, he’d always been the obedient son, but Rin just couldn’t! His father was going to be furious when he found out, but maybe Shiro would be proud of him… _fuck_ , he hated this goddamned war! Rin slammed his fists into the snow and shouted his frustration. 

Suguro coughed roughly from his spot nearby, curling into himself as he sucked down frigid lungfuls of air, and Rin spun to strike him, hand raised, muscles shaking with tension. He could still do it, he could kill him, finish him and be done with it-

Rin dropped his hand, defeated and tired and over the idea of fighting anymore, his adrenaline and bloodlust fading. Eventually he sighed, pushed to his feet, shook off the collected snow, and held out his hand to the other prince. “Come on,” he said quietly, “you’ll die if you stay out here much longer.”

The man didn’t move. Whether he _wouldn’t_ or _couldn’t_ , Rin wasn’t sure. “Fine, you baby, I’ll carry you then.” He snagged Suguro’s fallen prayer beads from the snow before hauling the human onto his shoulder, shuffling him around until his decorated armor no longer threatened to stab him in the eye. “You better thank me for this later.” Rin mumbled, trudging over to the fallen kama. It hissed as he approached and Rin hissed back. “Shut up and follow me. I’m too tired to beat your ass again.”

With that, he turned and stomped his way towards the mountain tunnel he’d spotted earlier. He’d search the ruined buildings later for anything useful, but for now, he just wanted a warm spot to plant himself out of the wind. He could worry about the war and the repercussions of his actions later.

**Author's Note:**

> Thank you for reading my loves! Comments, thoughts, reactions, and unintelligible screaming are all welcome. :D
> 
> You can find me on Twitter [HERE](https://twitter.com/lore_shark). I mostly write for BNHA, but I'm happy to yell about Ao No Exorcist all day long!
> 
> You can find Lakes and more of her amazing art on Twitter [HERE](https://twitter.com/lakes_northern). Go say hi!


End file.
